Modelling the Flow Behaviour of Al Alloy Sheets at Elevated Temperatures Using a Modified Zerilli-Armstrong Model and...

Area of Science:

• Materials Science
• Mechanical Engineering
• Metallurgy

Background:

• The flow behavior of AA2060 Al alloy under warm/hot deformation is complex, influenced by strain rate, strain, and deformation modes.
• Accurate prediction of this behavior across a wide range of temperatures and strain rates is crucial for material processing.

Purpose of the Study:

• To reveal and predict the warm/hot deformation flow behaviors of AA2060 Al alloy sheet.
• To develop and compare constitutive models for precise flow stress prediction under varying conditions.

Main Methods:

• Isothermal tensile tests were conducted using a Gleeble-3800 thermomechanical simulator at temperatures from 100-500 °C and strain rates from 0.01-10 s⁻¹.
• Three phenomenological models (L-MJC, S1-MJC, S2-MJC) and a physically based modified Zerilli-Armstrong (MZA) model were developed.
• Model predictability was assessed using statistical parameters: correlation coefficient (R), average absolute relative error (AARE), and root mean square error (RMSE).

Main Results:

• The S2-MJC model demonstrated the closest alignment between predicted and experimental stresses, outperforming S1-MJC, L-MJC, and MZA models.
• Statistical analysis confirmed the superior accuracy of the S2-MJC model.
• The enhanced predictability of S2-MJC is attributed to its effective linking of softening, strain rate, and strain hardening.

Conclusions:

• The S2-MJC constitutive model provides a highly accurate prediction of AA2060 Al alloy flow behavior under warm/hot deformation.
• The model's success stems from its ability to correlate dynamic recovery and softening mechanisms with strain, strain rate, and temperature.
• This research offers a reliable tool for predicting and optimizing the processing of AA2060 Al alloy.